System of telegraphic distribution



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1 M. PoTTs SYSTEM OF TELEGRAPHIC DISTRIBUTION Filed April v, 1920 s sheets-sneet 2 I:llllllllIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII y llllllllllllllllljlllll]llllllllllllllul .April 2L i925 '1,534,56I

L. M. POTTS SYSTEM OF TELEGRAPHIC DISTRIBUTION 3 Sheets-Sheet 5 Filed Apiil '7, 1920 A 7 ORN/5 Y.

.Patented Apr. 21, 1525. i .nutren 'ras- LoUIs M. rorrs, lor BALTIMORE, MARYLAND, AssIGNon, BY MESNE AssmNMENns, To AMERICAN TELEPHONE AND TELEGRAPH coMrANY, or NEW YORK, .N. Y., A

'conronA'rIoN or NEW Yonx.

SYSTEM OF TELEGRAPHIC DISTRIBUTION.

Application med April v, 1920. serial No. 371,946.

To' all 'whom t ma-y'cmwem:

Be it known that I, LoUrs M. Porrs, a citizen of the UnitedStates of America, residing at altimore, State of` Maryland, have invented certain new and useful Improvements in Systems of Telegraphic Distribution, of which the following is a speciication. A

This invention relates to printing telegraph systems.

An object of the invention is to provide a system whereby avplurality of telegraph messages originating at separate stations .may be transmitted over a plurality of branch lines or extension circuits to a main station where the code combinations of message impulses are automatically and simultaneously transferred to a main line circuit for vtransmissionthereover, and vice versa.

Another object is the tem which is reliable an tion. Other objects will appear hereinafter.

revision of a syseiiiclent 1n opera- It is usual in a synchronous multiplexl to group the segments of the different channels together. If such a multiplex is to be distributed to different users on separate wires ,for each channel, it is usual tol provide a series of relays at central lfor repeating the messages. It has also been proposed to conne'c't together vsegments in groups so that the segments of each group are distributed at equal intervals around the distributor. Such a lnethod has been used to obtain a number of Morse transmissions on a wire.

It is, however, not eiicient since the Morse transmission has no predetermined time or phase relation to the impulses on the main lineV and the impulses on the main line must.

. efficiently ladapting the method to printing telegraphs. A

One class of printing telegraphs operated from signals composed of an invariable-fstart impulse followed by five code impulses and an interval separating the consecutive signals. The five code impulses being used in all combinations, so as to givev thirty two slgnals with five elements. The

start impulse serving to start both the sending and receiving apparatuses into operation atthe beginning of each signal, means being provided to automatically stop them at the end of each signal.

The invention is here shown in connection with a system using automatic tape transany of these' methods of operation.

The invention will be described by referring to the followingdrawings:

Fig. l shows two centrals and associated substations.

Fig. 2 shows the grouping of the segments. 'l

Fig. 3 shows line andbranch lines.

`Fig. 4 is an electrical diagram of `a station transmitting to central.

Fig. 5 shows the transmitter stepping cam. f

Fig. 6 is an electrical diagram of a.-cen-. tra] 'sending to a substation.

The invention will .be described with reference to a. system having a main line 1 (see sub- Fig. 1) connecting two central olfi'ces X and Y and operated as afour channel synchronous multiplex. Three substations X1, X2, and X3. are connected to central Xbby wires 2, 3 and 4. Three other substations Y1, Y2,Jand Y3 are connected to central Y by three wires 5, 6 and 7; One channel mayv operate apparatuses 8 and 9 local inthe centrals X and'Y and is useful as a check on the correctness of the operation ofthe main line. v

The distributors for the mainline have twenty one segments, and the signals onv the' branch line have seven time intervals, so

that if every third segment is used for each' transmission we willget three channels. iIt

. sov the impulses on the mainA i of the code. Fig. 2 shows three groups A,

\ used in the central ofiices a check is furnished onthe operation of the other channels. A signal on the branch line composed of the second and fourth code elements will be like the curve E inFig. 3, while the corresponding signal on the main line will be like curve F in Fig. 3. No time is used on the main line for the start impulse or the interval between signals, these are taken care of locally between the central officesv and substations as described later. i

In Figure 4 all the apparatus to the left of the broken line is located at lsubstation X1 and represents the transmitting part of the apparatus. It is to be understood, however, that receiving apparatus may also be located at each of the substations. All the apparatus to the right ofthe broken line in Figure 4 represents the apparatus at the central station X. Apparatus is here shown to receive signals from substation X1 and retransmit them to central station Y (Fig. 6). It will be also understood that in .practice at station X there may be apparatus for transmitting to substation X1 similar to the apparatus located at Y. To the left of the dotted line in Figure 6 is apparatus located at central Y to receive the signals from central X and to retransmit them to substation Y1. t will be understood that at the station Y there may be apparatus similar to that at X to receive signals from substation Y,L and to retransmit them to. central X. `To the right of the broken line in Figure 6 is shown apparatus at substation Y,L to receive the signals transmitted vfrom central Y. It is understood, as in the previous cases, that there maybe located at Y1 transmitting apparatus similar to .that shown at substation X1.

Speed control.

, a method of control by an electrically driven tuning fork at centrals X and Y is here shown and'at the station Y there is shown means to correct the phase of the tuning fork with respect to the line signals and thus synchronize the apparatus at the two central stations X and Y. The distributing apparatus at the substations X1 and Y1 is stopped at the end of each signal and started atl the beginning of each signal under the control of the apparatus at centrals X and Y.. thus keeping the distributing apparatus atl t'he substations in phase with the appa.- ratus at the central. The method of tuning fork speed control shown is fully described in my U. S. Patent 1,201,621 and will be only brieiiy described here.

'At substation X1 there isa mbtor 10, which through gears 11 and 12 drives shaft 13, the functions of which will be later described. The shaft 14 of motor 10 carries rigidly fast thereto a sleevel and a sleeve 16 adapted to slide longitudinally thereon. One or more iiexible springs 17 have one end fast to sleeve 15 and the other fast to sleeve 16 and in the centre of each is rigidly fastened a weight 18. Sleeve 16 carries on the centre of its face an insulating tip 19 against which presses a spring 20 carrying on its tip a contact 21. Adjacent to spring 20 is mounted a similar spring 22 carrying a contact 23. The electrical connections are as follows: One terminal of the field and one armature brush of motor 10 are connected to the positive source of current supply (it is to be noted that all the'sources of current supply at each station are connected to the same source except in the casenof the signailing current). The other terminal of the field is connected direct to the negative source and the other armature brush through resistance 24 to negative. Contact 23 is connected to negative and contact 21 is tapped to the end of resistance 24, where it connects to the brush of motor 10. As motor 10 rotates and changes its speed weights 18 will move out and in slide sleeve 16 longitudinally on shaft 14 and thus open and close contacts 21-23 and open or close theshunt' circuit around resistance 24 and so regulate the amount of current flowing in the armature of motor 10. By properly choosing the springs 17 and weights 18 and adjusting contacts 21 and 23 the speed of motor 10 may b-e made whatever is desired. The relation of the speed of motor 10 to the other apparatuses will be fully explained later.

' At central X is a motor 25, which through gears 26 and 27 drives the brush arm 28 which carries two trailers 29 bearing on collecting ring 30 and a segmented ring 3l f having forty two segments, twice as many as the sending and receiving rings. Alternate segments of ring 31 are connected together and are connected respectively to contacts 32 and 33 between which vibrates a tongue 34 adapted to alternately engage contacts 32 and 33. -Tongue 34 is carried on one prong of a tuning fork 35. An electromagnet 36 has one terminal connected through a resistance 37 to the positive terminal of the direct current source of supply. The other terminal of magnet 36- connects to contact 38. In its normal position tongue 34 touches contact 38 and thus closes s and to open the circuit of magnet 36 at contacts 34 and 38 and thus allow the prongs of'tuning fork 35 to spring open again. The continued action of magnet 36 and contacts 34 and 38 will cause fork 35 to vibrate continuously. One terminal of the iel'dyand armature brush 39 of motor 25 are connected directly vto the sitive terminal of the current supply, t e other terminal of the field is connected to negative and armature brush 40 is connected through a resistance 41 to the negative terminal of the current supply and collecting ring 30 is also connected to brush 40. It will be noted that Vas trailer brushes 29 pass over successive segments ot segmented ring 31 and as ltongue 34 alternately engages contact:- 32 and 33, the resistance 41 will be shunted at rapidly recurring intervals and the motor armature will be receiving current daling certain intervals` only through resistance 41 and at other intervals will receive current digectly from the negative source. The length' the intervals during which the resistance 41 is shunted will depend upon the hase relation between the vibration of' the tuning fork 35 and the rotation of trailer brushes 29. The

V speed of the motor having been so regulated to pass from one contact 32 to the other 33,' the motor will come up to approximately the rcrrect speed and will quie 1y assume such a phase position' that the motor will automatically receive the correct amount of current to drive it ata speed corresponding to the rate of the "tuning fork. If the motor rends to go tooV fast, for example,`due to a rise of voltage, the length of the intervals during which the resistance 41 is short circuited will be decreased, the amount of current flowing into the motor will be decreased and the speed will be maintained. Any other tendencies to speed .cfhange will be inilarly compensated for.

At the central Y there is located an electrically driven tuning fork 42, electric motor 43, trailer brushes 44 driven through gears 45 and 46 by motor 43. Trailer brushes 44 pass over collecting ring 47 and segmented ring 48. Segmented ring 48 has the same' number of segments as segmented ring 31. Alternate segments of segmented ring 48 are connected ,to the contacts 49 and 50, which are alternately engaged by\tongu'e 51,-carried by tuning fork 42. Operatingmagnet 52`of tuning fork 42 has one terminal connected to vibrating tongue 53 of main line relay 54, connected in trunk` ,line 1 and operated by the current passing over said line. The other terminal of magnet 52 is connected midway between two condensers 55 and 56, the other terminal of reversals of the line current.

. holes 67.

from contact 58 to 59 or vice versadue to a reversal ofthe line current condensers 55 and 56 are charged and discharged through magnet 52. The impulses so formed at succeeding reversals of the line current main tain the motion of fork 42'in phase with the segmented ring 48, gea-rs 46 and 45, and tuning fork 42 being identical with the corresponding parts at central X, trailer brushes 44 will more in synchronism with trailer brushes 29 at station X.

- It is'to be noted that segmented ring 48 has twice as many segments as the'number of unit impulses transmitted on line 1 during one revolution of. the trailer brush 44. The reason for this number of segments in vring 48 is that the tuning fork 42 must always be in the same phase position at each reversal of the line current so that .thecorrecting impulses may always operate inthe same phase of the tuning fork, as more 'ully explained in my Patent 1,201,621 previously referred to.

At station Y1 there is a motor 60, centrifu i gal regulator 61, driving gears 62 and 63,`

all similar to the corresponding parts at sub-station X,L and performing in a similar manner.

Transmission from substation.

At substation X1 is shown an automatic transmitter controlled by perforated tape, any other'method of transmission may of course be used. This method is shown as one way of carrying out the invention. The automatic transmitter comprises five slides 64a to 64"'. The slides 64 to 64e carry on their upper end' pins 65a to 65?, adapted to engage the under surface of the perforated paper strip 66. 'i The paper strip 66 has a central row of perforations 67 called feed holes. A series of holes 68 has previously been perforated in any suitable manner in the tape in various combinations to represent the signals to be "that, as theftape 'is moved alonglstep by step by a mechanism described below, the perforations 68 will successively come into alignment with the corresponding pins 651L to 65". The perforated tape 66 passes over a cylinder 69 carrying a,y row of equally spaced pins 70, adaptedto enga-ge the feed Cylinder 69 has mounted on,

one end a ratchet wheel 71, a pawl 72 en gages ratchet wheel-71 andis pivoted to anQ 130 J pivoted at av point 78 (see Fig. 5). Arm 77 engages the circumference of adisc 79, which carries a cam projection 81. Disc 79 is rotated `intermittently by means later described. As disc 79 -is rotated the high part 81 of disc 79 will engage projection 80 on arm'77, push it downward, turn arm 73 about its pivot 82 andcause pawl 72 to-en gage ratchet wheel 7l and advance cylinder 69 one step and thereby paper strip 66 will lbe advanced one step, or the distance between two .succeeding groups of perforations 68. J ust as disc 79 comes to rest, arm 77 will rise and with it link 76, arm 73, and

I pawl 72. Pawl 72 will then be allowed to engage the next tooth 'in ratchet 71. By the repetition of this process paper strip 66 is advanced step by step. On the opposite end of cylinder 69 is a star wheel 83, acorrecting arm 84, whose Wedge shaped tip is vpressed by spring 85 into the notches in star wheel 83, thus insuring a positive stopping position for tape 66 so that perforations 68 will be in alignment with corresponding pins 65a to 65e.

Slides 646 to 64e are each pressed upward by individual springs 86. The slides 64a to 64e carry horizontal arms 87 which project under the arm 73. As arm 73 is movedup and down by the action of the disc 79, the

pins 65a to 65e are successively moved away from the paper strip 66 and again allowed to engage with the paper under tension of springs 86. Slides 64a to 64 also carry arms with insulated tips 88n to 88e. The tips 88a to 88e in their downward position engage a series of stops 89a to 89e, and 'in their upward positiorra series of contacts 90a to 90e. lVhen arm 73 rises and allows pins 65a to 65e to move upward, if any pin 65a to 65e engages a portion of the paper containing no perforation corresponding insulated tip 88a to 88e will remain in engagement with the corresponding lower stops 89EL to 89e. If, however, any pin 65a to 65e engages a perforated portion of stripA 66, the corresponding insulated tip 88a to 88c will engage the corresponding upper contact 9.0a to 90e. It will be noted then` that as paper strip 66 is stepped along, the insulated tips 88a to 88e will successively assume combinations of positions corresponding to the combinations of pcrforations 68 in strip 66.

Gear 12 is rig'dly attached to shaft 13, Fast to shaft 13 are two collars 91 and 92, and mounted loosely on shaft 13 is disc 79. A. spring 93 presses at one end against collar 92 and at the other end against disc 79, thus creating a pressure between disc 79 and collar 92, consequently as shaft 13 is continuously rotatemd by motor 10, disc 79 will tend to rotate.; Diso 79 carries an insul-ated arm 94. The tip of arm 94, enga-ges arm 95, pivoted about point 96 and normally held against stop 97 by spring 98. Vhen arm is against-stop 97, arm 94 will be prevented from rotating.l Arm 9.3, however, is adapted to be operated by a magnet 99. Magnet 99 has ,one terminal connected through a resistance 100 to the positive supply main. The other terminal of magnet 99 is'connected to Contact 101 of neutral relay 102. Tongue 103 of relay 102 is connected to negative. Spring 104 normally holds tongue 103 against stop 105.V One terminal of the coil 106 is connected 'to ground, through a switch 107, the func` tion of which will be described later. The other terminal of coil 106 is connected to segment 108 of segmented ring 109. Segmentedring 109 is so oriented that a trailer brush 110 stops on segment 108, when the tip of arm 95 engages arm 94. Connected to arm 94 is another trailer british 111, adapted to engage collecting ring 112. Collecting ring 112 is connected to branch line 2. Segmented ring 109 contains siX equal segments. Segments 113a to 113a are connected to the corresponding, insulated tips 88a 'to 88e. Contacts 90a to 90e are all connected to ground. vLine 2 passes to central and connects through relays 114 or 115 and 116 and resistance 117`to one pole of generator 118, the other terminal of which connects to ground.

The mechanical details'having been described and the electrical connections traced the operation of transmitting from substation. X1 to central X will be briefly described. It will be assumed that the tip of arm 95 engages arm 94. A circuit will now be completed from the positive pole of generator 118, through resistance 117, relay 116, relays or 114, line 2 as later described,

collecting ring 112, trailer .brush 111` arm 110 94, trailer brush 110, segment 108, coil.106. switch 107 to ground and back to the negative brush of generator-118. Magnet 106 will be energized, tongue 103 will engage contact 101 and thus complete a circuit trom 115 positive through resistance. 100. coil 99, contact 1015tongue 103 to negative. Magnet 99 will be energized, arm 95 attracted and disengaged from the tip of arm 94. Arm

94 and trailer brushes 110 and 111 will ro- 120 tate with shaft 13. As trailer brnsh'110 passes from segment 108 the circuit of coil 106 will be'broken and thereby the circuit of magnet 99. Arm 95 will return to stop 97 undertension of spring 98, and will be 125 in a position to stop arm 94 upon the completion of one revolution. As trailer brush 110 passes to segments 113 to 113e current will be transmitted to line or not depending upon whetherthe corresponding pins 65HL to 130 65 have been prevented from rising by the paper 66 or have been allowed to rise in vconsequence of being opposite a perforation 68. 1f ay pin 65a to 65 is opposite a perforation a circuit will be completed as follows: from the positive terminal of generator 118 resistance 117, relay 116, relays 115 or 114,line 2, collectin ring 112, trailer brush 111, arm 94,'trailer rush 110, segment 113 to 113, insulated tips 88a to 88, contacts 90 to 90, to ground. If a pin 65n to 65 engages an unperforated portion of paper stripx66, the' over corresponding segments of segmented-v rings 109 and 120 at the same time, or, in

. other words, that trailer brush 110 shall be started at the beg'mning of a signal by an impulse sent when trailer brush 119 is passing over segment 121. Relays 114 and. 115 perform this function. Relay 114 is a neutral relay.- Itscircuit is traced as follows: positive through a resistance 122, coil 123, switch124, segment 125, trailen brushes 126, collecting ring 127, to negative. It will be noted that by this arrangement when trailer brush 126 reaches segment 125, the above circuit will be closed and tongue 128 Will make contact with contact 129, and close the line circuit through forward coil 130 of polarized relay 115, provided switch 107 at substation X1 is closed and trailer brush 110 is on segment 108. Tongue 131 o-f relay 115 will then go forward and make contactwith contact 132 and relay 115 being a polarized relay the line 2 will remain closed at central X untiltrailer brush 126 reaches segment 133. When such is the case a circuit will be closed as follows: positive supply main, resistance 134, back coil 135 of relay 115, segment 133, trailer brushes 126, collecting ring 127 .to negative. Tongue 131. will"be pulled away from contact 132 and the line will be again opened at contacts 131 and 132. If when trailer brush 126 reaches segment 125, the swltch 124 at station X is open the relay 114 will not operate and brush arm 94 will then stop so that trailer brush 110 is on segment 108 and will not again start until switch 124 i'seclosed and will even then not start until trailer brush 126 reaches segment 125, so that the proper relation betweenthe rotation of trailer brushes 110 andv126 will be e maintained. It is to be noted that the transmission can thus be stopped at central X without splitting signals since the line cannot be opened until the signal is com-` plete.

It is to he noted that the start impulse and the lag interval between succeeding signals are both controlled by the sunflower device at central X and that only the code impulses are controlled by apparatus at the substation X1.

Transmission from central to central Y .Y At central X tongue 136i of relay., 116 isI .connected to'a grou of Segments 137'to 137' arranged accordlng to group A, Fig. 2.

As tongue .136 vibratesunder the control of the tape' transmitter at substation X1, and trailer brushes 119 rotate in step with trailer brushes -111, impulses like curve F, Fig.'3, will be transmitted over a circuit as followsfpositive pole of generator 138 or negative pole of generator 139, resistance 140 01'141. back contact 142 or forward conr are so oriented with respect t'o one .another that segments 137 to 137 fall in the middle 4 of segments 113 to 113 as shown in curves.

E and F Fig. 3. By this arrangement vrelajyl 116 Will-transmit perfect signals on linel, even though the signals actuating relay 116 from line 2 may be considerably mutilated.

Transmission from 'central y17 to .rubata-f l tion Y1.

Relay 148 wi1l receive during each revolution of trailer brushes 146 five impulses from segments grouped as shown in A Figure These impulses will move tongue 149 forward or back according to the signals sent. These impulses are sepa-rated by an interval twice as long as the impulses. Relay 148 being polarized' will remain in the position placed by one impulse until it receives the next impulse, so that for each of the shortl impulses transmitted over line' 1 relay 1.48

will rexnairnin a'corresponding position three times the length of the short impulse or a length of time equal to the length of theorigmal impulses transmitted over line 2. During the interval occupied by trailer brushes 146 inpassing over segments 150 to 150 and 150x, corresponding to group D Figures 2, relay 148 isl not controlled byim- 513 negative.

pulses on line 1 and distributed by segmented ring 151, but by local impulses distributed by segmented ring 152. Segment 153 is connected to the'positive pole of generator 154 through resistance 155 and segment 156 is connected to the negative pole of generator 157 through resistance 158. 159 and 160 are connected to relay 148 along with the segments 147a'to 147e and together v they are adapted to give to vrelay 148 seven impulses having equal time interval. between each two succeeding impulses. Five of the seven impulses are controlled over line 14 and two locally, one of the later invariably positive and the other invariably The circuit of the positive impulse, which controls the start impulse, may be traced as follows: positive pole of vgenerator 154, resistance 155, segment 153,

-referred to in the preceding paragraph, the

tongue 149of relay 148 will vibrate like the tongue 136 of relay 116 and send an invariable startimpulse followed by a combina- Vtion 'of the live impulses corresponding to the signal sent and a lag interval after the five code impulses over a circuit which may be traced as follows: positive pole of 'generator 162, resistance 163, tongue 149, contact 164, line 5, coil of relay 165, to ground and return.

Reception at substation Y1.

At station Y, there is a brush arm 166 fastened to a disc 167 but insulated therefrom.

vDisc 167 is mounted loosely on shaft 168 Ywhlch is rigidly attached to gear 63. Rigidly attached to shaft 168 is a collar 169 against which disc 167 is pressed by spring 170, the other end of sprin@ 170 presses against a collar 171 also rigidly attached to shaft 168. By this pressure friction will be maintained between disc 167 and collar 169 and as shaft 168 is driven byy motor 60, there will be a tendency for arm 166 to rotate. However, arm 166 is normally prevented from rotating by arm 172, which is held against stop 173 by spring 174 and arm 166 remains at rest with a tendency to rotate except when arm 172 is moved, as explained later. Arm 166 carries trailer brushes 175 and 176. Trailer brush 175 passes over collecting ring 177 which is connected to the forward contact 178 of relay 165. The

tongue 179 of relay 165 is connected to negative. Trailer brush 176 passes over segf mented ring 180. Segment 181 upon which Segments -A trailer brush 17 6 normally rests connects to one terminal of magnet 182, the other terminal ofwhich connects through resistance- 183 to positive. The remaining segments 184a to 184e are connected to'one terminal of T' a series of magnets 185a to 185e, the other terminals of which are connected together and through resistance 186 to positive.

The operation of receiving signals at substation Y1 will now be described. lVhen re- 7 lay 165 is operated by the start impulse on line 5 tongue 179 will engage contactl 17 8 and will complete a circuit as follows: positive terminal, resistance 183, magnet 182, segment 181, trailer brush 17 6, brush arm 166, trailer brush 175, collecting ring 177, contact 178, tongue 179, to negative. Magnet 182 will thus 'be energized and attract arm 172 and release brush arm 166 and allow it to make a complete revolution. trailer brush 17 6 reaches segment 184a a circuit may be traced as follows, provided the signal being transmitted involves the A element: positive terminal, resistance 186, magnet 185% segment 184% trailer brush 176, and as previously described in connection with the lstart impulse. If the signal being transmitted does not contain the A element the circuit will be open and magnet 185a will not bel energized.` In a similar 9 manner the other magnets 185b to 185e may lVhen Si be operated. The magnets 185a to 185e may be the selecting .magnets for any suitable recording mechanism. For example, they may be theselecting magnets in my U. S. 5'

Patent 1,309,745 granted July 15, 1919. The live selecting magnets being operated in all combinations so that the recording mechanism may record thirty two Adifferent Signals.

So far only thejoperation from substation X, to Y1 has been described. This only 1nvolves the groupof segments A Fig. 2. The group of segments B, C and D Fig. 2 are c connected together and used in a manner 1l similar to the group A to provide communication between other substations, X2, X3, Y2 and YS. In Fig. 4 segments 187a to 187e are connected together and connect to the tongue 188 of a, relay 189. The coil of relay 189 is connected to a resistance 190 to generator 118. Associated with relay 189 are two relays 191 and 192 which correspond to relays 114 and 115 and perform the same function fo-r line 3. Lilie 3 may connect to a transmitting device -similar to the one shown at substatio-n X1 and described above. Relay 189 will transmit on line 1 a series of impulses for the group of segments B similar to the group transmitted for group A. At l central `Y there is a relay 194 which is connected toa group of segments on segmented ring 151 and segments on segmented ring 152 in the same manner as relay 148. /Relay 194 is controlled by the impulsesset out by 1 Lussac:

relay 4189' at central X. Tongue 195 connects through resistance 196 to positive pole of generator 162 and contact 197 connects to a line 6 which may goto a substation Yz and control selective apparatus theresimilar to the apparatus at Y1. The segments corresponding to the group C may also be connected and operated in a similar manner. The group D may be used to operate locall apparatus 8 and 9. A Y

Attention is called to the fact that the front contact 143 of relay 116 is connected to the negative pole ofgenerator 139 and the back coniact`142 to positive pole ofgenerator 138, while the contacts of relay 189 are reversed i. e. front contact 199 is connected to the positive pole of generator 138 and back contact 200 to negative )ole of generator 139. This is done in ort er that there may bereversals on line 1 even where none of the channels are in operation and 1s essential for the purpose of maintaining synclironism between the sunflower devicesat central Y and Y asexplained above.

Refer to Figure 3. The curve :E represents the signals on branch line 2 for a signal lcomposed of the secondand fourth elements of the code. Curve F shows the same signal on the main line. Attention is called to the fact that tlie impulses on the main line are one-third the length of the corresponding impulses on the b: ancli line and that the impulses-on the main line fall in the lmiddle of the impulses on the branch line. The relay tongue 136 operates from-the impulses on the branch line before the 'corresponding impulse is transmitted on the. main line and the impulse on the main line is completed before the relay tongue operates for the next impulse on the branch line, so 4that any irregularities in the beginning or ending ofthe impulses on the branch line will not affect the main line impulses. The amount -of margin is approximately the time interyval of an impulse on themain `line both at "the beginning and end of the impulses so Vralitypf characters, dividing the impulses code combinations of message impulses in 'aceordance with the impulses on the main line, each im ulse of the group immediately succeeding t e preceding impulse of then y same group without an* appreciable time inof the several characters into groups, separating each impulse of theV groups by the same number of impulses of other groups, transmitting o'n the @branch line a. gro-up of consists in transmitting on said branch line La series'of groups of code combinations of message impulses, each group representing a signal, each of the impulses of a group' succeeding` the immediately preceding impulse without an appreciable time interval between the end of one impulse and the beginning of the next succeeding impulse, each of said groups having the same number of impulses,tlie impulsesof each group varying, in combination to represent different signals, and transmitting on said main line a grou a of impulses each controlled by a co-rrespon ing impulse of the said group of impulses transmitted on the branch'- line, succeeding impulses of the group transmitted on the main line being separat-ed by the same numberof impulses belonging to `groups independent of the group controlled by impulses trans.

mitted on said branch line.

3. In a telegraph system, a main line, synchronous multiplex telegraph apparatus operable `'over said main line, an extension circuit, telegraph "apparatus arranged to .transmit over said extension circuit a start impulse followed bycode combinations of message impulses, a relay operated by-all of the impulses on said extension circuit, and means including said synchronous multiplex telegraph apparatus to transmit over said main line current impulses to represent said code combinations of message. impulses from contacts operated by said relay.

4. In a telegraph system, multiplex synchronousl telegraph transmitting apparatus, a single 'transmitting relay to control the transmission of all the code combinations of message impulses for one channel of said multiplex, distantly controlled means to coutrol said relay during the transmission of said impulses, and local means to control said rela-y during certain other intervals.

5.v -In a telegraph system, selective receiving nieanscomprisinga series of elements operated -in combinations, a synchronous multiplex telegraphreceiving device accommodating a plurality of channels, inea-ns to transmit code combinations of message iinpulses to said multiplex receiving device, an extension circuit extending between said selective receiving means and one channel of said multiplex receiving device, and a relay `for each channel 'ofV said receiving device individual; to the segments in said channel for transmitting directly to the extension circuit `impulses from said synchronous multiplex receiving device to aect the operation of said selectivevrecelvmg devlce.

means to transmit code combinations of mes- 6. In a telegraph system, a main e,"

loa

sage impulses' on said main line, a continuously rotating sun-flower device having the segments thereof arranged in groups, a single relay connected directly to the segments in one of said groups, selective receiving means controlled by said relay in response to code combinations of message impulses, and a'n intermittently rotary distributor for distributing the impulses transmitted by said relay to said selective receiving means in the proper order.

7. In a telegraph system, a central station, a substation, automatic transmitting means at said substation for transmitting code combinations of message impulses, a continuously rotating sun-flower device at said central station having certain segments thereofv connected in groups, a single relay connected directly to all the segmentsl in one of said groups, a main line, means for transmitting the code combinations of message impulses from said transmitting means at the substation to said main line, Itiming means located at the central station for regulating the rotation of said sun-flower device, and timing means at the' substation for regulating the transmitting' means and so adjusted that said relay operates with a definite time relation to the speed of said sun-flower device. .L

8, In a telegraph system, a main'line, a branch line, means to transmit impulses on said main line, a sunflower device adapted to distribute the impulses transmitted over said niain line, a sunflower device adapted to distribute impulses generated locally, a relay having its coils connected to a group of segments of said first mentioned sunflower device, said coils also being connected to certain segments of said second mentioned sunflower device, and contacts operated by said coils so as to transmit on said branch line successive groups of impulses, each group representing a signal, each signal comprising an invariable part controlled by the impulses distributed by the second mentioned sunflower devicey and a variable part controlled by the impulses distributed by said first mentioned sunflower device.

9. In a telegraph system, a branch office, a

central station, a branch line connecting said branch station to said central station, means located at the branch oflice to transmit over said branch line code combinations of message impulses, a relay operated by said impulses, a sunflower device, a contact operated by said relay and connected to a group of segments on said sunflower device, consecutive segments of said group being separated by the same number of segments connected to controlling means independent of said relay, the last segment of said group being separated from the first segment of said group by a larger number of segments than separates consecutive segments, said last mentioned separating segments being also connected to controlling means independent of said relay, a main line, and means including lthe contact of said relay and said sunflower device to transmit on said main line code combinations of message impulses corresponding to said impulses transmitted on said branch line.

10. In a telegraph system, a main line,

means to transmit electric impulses on said line, a polarized relay, synchronous telegraph apparatus comprising a sunflower device adapted to distribute certain of said impulses to said relay, the coils of said relay being connected to a group of segments of said sunflower device equally spaced apart and separated by the same number of segments connected to apparatus independent of said relay, the last segment of said group being separated from the first segment by a greater number of segments than separate the consecutive segments, a local sunflower' device, said coil also being connected to certain segments of said local sunflower device located so as to control said relay in the long interval between the last segment and first segment of the said group of segments on the first mentioned sunflower device, a branch line, a contact controlled by said relay and connected in said branch line, means including said contact to transmit on said branch line impulses corresponding to the impulses distributed by the first mentioned sunflower device to said relay.

In testimony whereof I affix my signature.

LOUIS M. POTTS Sfr 

